fujitsu-laptop: driver [un]registration fixes

* Move led_classdev_unregister() calls from fujitsu_cleanup() to
  acpi_fujitsu_hotkey_remove().

* Fix ordering in fujitsu_cleanup().

* Fix backlight_device_register() failure handling in fujitsu_init().

* Add missing sysfs group removal on failure to fujitsu_init().

* Add input device unregistering on failure to acpi_fujitsu_add()
  and acpi_fujitsu_hotkey_add().

* Add input device unregistering/freeing to acpi_fujitsu_remove()
  and acpi_fujitsu_hotkey_remove() (also remove superfluous 'device'
  and 'acpi_driver_data(device)' checks while at it).

* Do few minor cleanups.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Acked-by: Jonathan Woithe <jwoithe@physics.adelaide.edu.au>
Signed-off-by: Len Brown <len.brown@intel.com>